Data transmission device



FIG. 1 is a perspective view of a data transmission device showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a back view thereof;

FIG. 6 is a left end view thereof; and,

FIG. 7 is a right end view thereof. 

The ornamental design for a data transmission device, as shown and described. 